Some people have a gift for music. After listening to a song played just once, they can play it themselves. Other people sing beautifully. And still others have what's called perfect pitch - the ability to tell exactly what note is playing and whether it's in tune.

It's obvious that these musical abilities run in some families. These families have homes filled with music, and family members often play an instrument. But is this ability in their environment or in their genes?

Dr. Jane Gitschier from the University of California, San Francisco thinks that at least one musical talent is inherited. Perfect, or absolute, pitch is the ability to tell if a note is in tune.

"In other words, if someone were to play a C-sharp on a piano, an individual with perfect pitch - or absolute pitch, which is the more formal word for it - hears that," she says. "They will be able to say, 'That is a C-sharp.'"

Gitschier says current evidence shows that only about one in 10,000 people have absolute pitch. And she says part of the talent does depend on receiving enough musical training to know what to call the notes when they hear them.

"A lot of people who do have perfect pitch realize that they can do this. But they think that everybody can do it," Gitschier says. "And it isn't until they're, say, teenagers and in an orchestra or a chorus or something and it becomes obvious that they're the only person in the room that can do it."

To study families and perfect pitch, Gitschier created a Web site. It includes a page where people could test themselves to see if they had that ability. She asked musicians to take the test and asked members of their families to take it as well. Then she asked them for blood or skin samples, so she could examine their DNA. She looked at about 80 families, the majority of whom were of European ancestry.

"We found a region of the genome on chromosome 8 that appears to have a gene in it that may be responsible for the acquisition of absolute pitch in that population," Gitschier says.

Knowing about absolute pitch is interesting, but as a practical matter, Gitschier says studying the phenomenon can tell scientists about the brain. Other studies have shown that people with absolute pitch actually have both structural and functional differences in their brains compared to people who have early musical training but don't have absolute pitch

"So, this is a way of getting to look at specific genetic factors that altered the way our brains develop," Gitschier says.